Drive assembly with selective disconnect

Abstract

A drive assembly with selective disconnect includes a motor with a motor drive shaft; a harmonic drive coupled to one end of the motor drive shaft; an output shaft coupled to the harmonic drive; and a retracting mechanism that selectively retracts the motor drive shaft axially to decouple the motor drive shaft from the harmonic drive.

1 . A method comprising:
 driving an output shaft with a motor drive shaft through a harmonic drive located between the output shaft and the motor drive shaft; and   disconnecting the output shaft from the motor drive shaft by selectively decoupling the motor drive shaft from the harmonic drive.   
     
     
         2 . The method of  claim 1  further comprising:
 preventing the motor drive shaft from axial movement. 
 
     
     
         3 . The method of  claim 1 , wherein the motor drive shaft is attached to a wave generator within the harmonic drive and the wave generator is retracted from the harmonic drive when the motor drive shaft is disconnected from the harmonic drive. 
     
     
         4 . The method of  claim 3 , wherein the motor drive shaft and the wave generator are selectively retracted by a spring. 
     
     
         5 . The method of  claim 4 , wherein a solenoid selectively retracts a locking mechanism to unlock the motor drive shaft and allow the spring to retract the motor drive shaft and the wave generator. 
     
     
         6 . The method of  claim 4 , wherein the motor drive shaft and wave generator selectively retract in response to feedback from the electric motor, motor drive shaft, or output shaft.